37results about How to "Inhibition of decarburization" patented technology

The steel wire material for a spring of the invention contains; C: 0.37-0.54%, Si: 1.7-2.30%, Mn: 0.1-1.30%, Cr: 0.15-1.1%, Cu: 0.15-0.6%, Ti: 0.010-0.1%, Al: 0.003-0.05%, and the balance including iron with inevitable impurities, wherein ferrite decarburized layer depth is 0.01 mm or less, whole decarburized layer depth is 0.20 mm or less, and fracture reduction of area is 25% or more. It alternately may contain; C: 0.38-0.47%, Si: 1.9-2.5%, Mn: 0.6-1.3%, Ti: 0.05-0.15%, Al: 0.003-0.1%, and the balance including iron with inevitable impurities, wherein ferrite decarburized layer depth is 0.01 mm or less, Ceq1 in the equation (1) below is 0.580 or more, Ceq2 in the equation (2) below is 0.49 or less, and Ceq3 in the equation (3) below is 0.570 or less.Ceq1=[C]+0.11[Si]−0.07[Mn]−0.05[Ni]+0.02[Cr]  (1)Ceq2=[C]+0.30[Cr]−0.15[Ni]−0.70[Cu]  (2)Ceq3=[C]−0.04[Si]+0.24[Mn]+0.10[Ni]+0.20[Cr]−0.89[Ti]−1.92[Nb]  (3)(In the above equations, [ ] shows the content (mass %) of each element in steel.)

The technology described herein provides a method and system to prevent iron oxide formation and decarburization during strand heat treating of a steel product without the subsequent required use of acid pickling, which has associated health and environmental risks. Additionally, this technology provides placing a coating, such as copper plating, to the surface of a steel wire prior to strand heat treating to avoid both iron oxide formation and decarburization through the surface of the steel wire by preventing interactions between the steel wire and the furnace atmosphere. To remove oxides formed by the plating metal, the oxides are chemically reduced by passing the steel wire through a reducing gas, electrolytically reduced by plating with the wire anodic, mechanically reduced through the use of brushes, or the like, or chemically reduced by acid pickling.

The invention relates to a wolfram carbide-cobalt-carbon composite powder for hot spraying and a preparation method thereof. The invention is characterized in that the composite powder contains simple substance carbon, and is composed of the following components in percentage by weight: 5-30% of Co, 60-90% of WC, 1-10% of C, 0-20% of Fe and 0-20% of Cr. The preparation method comprises the following steps: proportionally and directly mixing graphite powder used as a carbon source with other powder components, carrying out ball milling or high-energy ball milling mechanical alloying under the protection of absolute alcohol, kerosene or any other organic solvent, drying, and screening to obtain the composite powder. The invention can also comprise the following steps: by using an organic compound (such as glucose) as a carbon source, proportionally and directly mixing powdered glucose with other powder components, carrying out ball milling under the protection of absolute alcohol, kerosene or any other organic solvent, drying at 60-80 DEG C, carbonizing in a vacuum furnace at 400 DEG C below, carrying out ball milling or high-energy ball milling mechanical alloying, and screening to obtain the composite powder.

The invention discloses a method for preparing a Ni-Fe-based high-temperature binder phase hard alloy. The method comprises the following steps of firstly mixing nickel powder, iron powder, chromium powder, molybdenum powder and aluminum powder in a predetermined mass ratio and carrying out high-energy ball milling; carrying out ordinary ball milling on powder subjected to high-energy ball milling, tungsten carbide powder, titanium carbide powder and vanadium carbide powder to obtain a mixed powder; loading the prepared mixed powder into a mold and pressing by virtue of cold press to obtain a green body; carrying out sinter molding on the green body material under the protective atmosphere to finally obtain the Ni-Fe-based high-temperature binder phase hard alloy material. According to the method, Ni-Fe-based mechanical alloying powder instead of Co powder is used as a binder, and the prepared hard alloy has Vickers hardness equal to or greater than 1530 / kg.mm<-2>, flexural strength equal to or greater than 4880MPa and tensile strength equal to or greater than 4562MPa at 1000 DEG C.

The invention relates to long-fatigue-life strip steel as well as a preparation method and application thereof, and belongs to the technical field of steel preparation. The long-fatigue-life strip steel is prepared from the following chemical components in percentage by mass: 0.26 to 0.45 percent of C, 0.10 to 0.25 percent of Si, 1.1 to 1.4 percent of Mn, less than or equal to 0.015 percent of P,less than or equal to 0.003 percent of S, 0.015 to 0.08 percent of Al, 0.01 to 0.05 percent of Ti, 0.0010 to 0.0050 percent of B, 0.10 to 0.30 percent of Cr, less than or equal to 0.006 percent of N,and at least one of the following chemical components in percentage by mass: 0.05 to 0.2 percent of Sb, 0.05 to 0.2 percent of Sn, and the balance of Fe and inevitable impurities. A hollow stabilizerbar is prone to surface decarburization in the plurality of heat treatment in the raw material production and follow-up forming process, so that the surface hardness is reduced, and the fatigue life is shortened. The tin / antimony element is prone to enrich on the surface layer of steel to inhibit the diffusion of C from the strip steel, so that decarburization of the surface layer is inhibited. Atleast one of Sb and Sn is added into the chemical components of the material, so that the fatigue life of the final part hollow stabilizer bar is prolonged by reducing surface decarburization of thematerial.

The invention discloses a furnace beam and vertical column fire-resistant thermal insulation lining structure of a walking beam furnace for heating high-temperature oriented silicon steel. The furnace beam and vertical column fire-resistant thermal insulation lining structure comprises a metal pipe forming a foundation of a furnace beam or a vertical column, wherein heat-resistant cushion blocks are arranged on the metal pipe forming the foundation of the furnace beam at intervals along the axis direction, metal anchoring parts are uniformly distributed on the outer wall of the metal pipe along the axial direction and the peripheral direction, a fire-resistant insulating layer is formed to cling to the outer wall of the metal pipe in a pouring manner and is combined with the metal anchoring parts, and the fire-resistant insulating layer is sequentially covered by a slag-bonding prevention layer and an anti-oxidation coating. As the heat preservation and slag-bonding prevention double-layer structure and the design of appropriate thickness are adopted by the furnace beam and vertical column fire-resistant thermal insulation lining structure of the walking beam furnace, the integrality of a thermal insulation lining is improved, and the comprehensive usability of the thermal insulation lining is improved.

The invention relates to a heat treatment process of brazing tool steel XGQ25 with gradient hardness distribution; and the process can realize reasonable gradient hardness distribution of a carburized brazing tool from the surface to the basal body. The process comprises the following steps: the carburized brazing tool is quenched and insulated by 60 minutes at 800+-10 DEG C, and is cooled by three stages after the insulation is finished; firstly, the oil cooling is performed to reach 400+-10 DEG C; then, the furnace cooling is performed to reach 200 DEG C, and the cooling speed is 0.05-0.1 DEG C / s; and then, the air cooling is performed below 200 DEG C to reach the room temperature. The tempering insulation is performed by 120 minutes at 200 DEG C; and the air cooling is performed to reach the room temperature after the insulation is finished. Through actuation of the process, the carburized brazing tool forms a high-carbon martensite structure (HV640-660) with high surface hardness, a lower bainite structure (no-gap impact power of 115-120 J) with high center toughness and a lower bainite and low-carbon martensite complex-phase structure with a wider transition layer (width of 0.5-1.0 mm), so that excellent toughness matchability is obtained, and the service life of the brazing tool is effectively prolonged.

A friction stir welding tool for welding of metallic plates and especially steel plates. The friction stir welding tool is made of cemented carbide comprising WC grains in a binder phase and wherein the welding tool is at least partly coated with a surface coating comprising Al2O3.

The invention discloses spring steel with good heat resistance and impact resistance and a production method thereof, and belongs to the technical field of spring steel production. The spring steel comprises the following chemical components of, in percentage by weight, 0.50 %-0.60 % of C, 1.60 %-2.20 % of Si, 0.80 %-1.00 % of Mn, 0.80 %-1.30 % of Cr, 0.20 %-0.50 % of Mo, 0.70 %-1.30 % of W, 0.20%-0.40 % of V, 0.02 %-0.04 % of Nb, 0.015 %-0.030 % of Ti, 0.15 %-0.30 % of Ni, 0.15 %-0.30 % of Cu, trace-0.015 % of P, trace-0.010 % of S, less than or equal to 0.0012 % of O, less than or equal to0.006 % of N and the balance Fe and other inevitable impurities. The production method of the spring steel comprises the steps of electric arc furnace smelting, LF furnace refining, RH or VD vacuum degassing, round billet continuous casting, square billet rolling, flaw detection, scaling, high-speed wire rod controlled rolling, stelmor cooling wire controlled cooling treatment and heat treatment.According to the technical scheme, the obtained spring steel has good heat resistance, impact resistance and hydrogen embrittlement fracture resistance, and therefore the use requirements of the spring steel at high temperature and high pressure can be effectively met.

The invention provides aluminum-containing high-strength steel and a preparation method and application of the aluminum-containing high-strength steel. The aluminum-containing high-strength steel is prepared from the following chemical components including, by mass: 0.1% to 0.2% of C, 0.3% to 0.6% of Si, 2% to 3% of Mn, less than or equal to 0.0015% of P, less than or equal to 0.0015% of S, 0.5% to 1% of Al, 0.1% to 0.3% of Mo, 0.01% to 0.05% of Pb and the balance of Fe and inevitable impurities. The aluminum-containing high-strength steel provided is good in surface and free of chromatic aberration defects after being galvanized.

The invention discloses steel for a single-layer concrete conveying pipe of a trailer pump vehicle and a production method thereof. The steel for the single-layer concrete conveying pipe of the trailer pump vehicle includes 0.38-0.48% of carbon, 0.05-0.35% of silicon, 1.60-2.50% of manganese, 0.0015-0.0030% of calcium, 0.35-0.65% of chromium, 0.30-0.50% of tungsten, 0.05-0.20% of erbium, 0.015-0.045% of aluminum, less than or equal to 0.010% of phosphorus, less than or equal to 0.003% of sulfur, less than or equal to 0.006% of nitrogen, and rest of iron and unavoidable impurity. The steel is high in wear-resisting property, the proper final rolling and coiling temperature is controlled in the production process, the standing time of a steel coil at a two-phase region is reduced, the steel is quickly cooled to a pseudo-eutectoid pearlite precipitation zone, the proeutectoid ferrite production is reduced, the proeutectoid ferrite is not generated in a slow cooling process after coiling, and meanwhile, the bainite formation due to a too low coiling temperature is avoided, and more pearlite is formed.

The invention provides a preparation method of a high-wear-resistance and high-corrosion-resistance protective layer of hot work die steel, and relates to the technical field of die steel. The preparation method of the protective layer comprises the following steps: (1) carrying out surface purification treatment and surface roughening treatment; (2) carrying out preheating treatment, then spraying a coating by adopting a hypersonic flame spraying method, carrying out compressed air cooling, and the spraying powder being prepared from the following components in percentage by weight: 55 to 64percent of WC, 12 to 18 percent of TaC, 3 to 4.5 percent of VC, 0.8 to 1.5 percent of nano rare earth oxide and the balance of NiCr; and (3) carrying out carburizing treatment, quenching and tempering. According to the method, the hot work die steel is subjected to surface roughening treatment, hypersonic flame spraying, carburizing treatment, quenching and tempering, so that a high-wear-resistance and high-corrosion-resistance coating can be formed on the surface of the hot work die steel, the bonding strength between the coating and a base body is high, and excellent surface protection and strengthening can be formed on the hot work die steel.

Provided is a raw material powder for powder metallurgy, capable of preventing stains, surface defects and decarburization of a sintered body, improving strength and density thereof. The raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C., composed of a mixture of a metal powder and a lubricant, in which the lubricant is melamine cyanurate or terephthalic acid. Alternatively, the raw material powder for powder metallurgy is for use in the production of a sintered body that is sintered at a temperature of not lower than 500° C., composed of a mixture of a metal powder, a first lubricant and a second lubricant, in which the first lubricant is melamine cyanurate or terephthalic acid, while the second lubricant is preferably erucic acid amide or stearic acid amide.

The steel wire material for a spring of the invention contains; C: 0.37-0.54%, Si: 1.7-2.30%, Mn: 0.1-1.30%, Cr: 0.15-1.1%, Cu: 0.15-0.6%, Ti: 0.010-0.1%, Al: 0.003-0.05%, and the balance including iron with inevitable impurities, wherein ferrite decarburized layer depth is 0.01 mm or less, whole decarburized layer depth is 0.20 mm or less, and fracture reduction of area is 25% or more. It alternately may contain; C: 0.38-0.47%, Si: 1.9-2.5%, Mn: 0.6-1.3%, Ti: 0.05-0.15%, Al: 0.003-0.1%, and the balance including iron with inevitable impurities, wherein ferrite decarburized layer depth is 0.01 mm or less.

The invention relates to a high-temperature surface carbon retaining isolation agent for medium-high-carbon steel and an application method of the high-temperature surface carbon retaining isolation agent. The high-temperature surface carbon retaining isolation agent comprises components including, by weight percent, 60%-85% of diopside, 1%-5% of nano silicon nitride, 1%-5% of nano chromium carbide, 5%-15% of aluminum ash powder, 6%-25% of potash water glass and 0.1%-0.5% of polyacrylamide, wherein the granularity of the nano silicon nitride and the granularity of the nano chromium carbide are100-500 nm, and the added water volume accounts for 60%-90% of the total weight. The above components are evenly mixed according to a mechanical grinding and mixing method to prepare the isolation agent with the granularity smaller than 100 microns. The isolation agent is suitable for high-temperature protection when a steel blank is heated at the temperature of 900-1,150 DEG C for 1-10 h, the isolation agent is sprayed to the surface of the normal-temperature steel blank, the thickness of the isolation agent ranges from 200 microns to 500 microns, a glass base protection film is formed in the temperature rise process of the isolation agent, and carbon oxygen mutual permeation of the surface of the base body is protected. After the protected steel blank is heated, the isolation agent andthe steel blank surface scales can be completely removed through high-pressure water descaling, the isolation agent achieves the function of carbon retaining, the rolled material surface decarburization layer depth is effectively reduced, the rolled material surface quality is improved, and the usage cost is low.

The hardened steel tube member is formed from a GI zinc-coated steel tube. The cross-section, which is perpendicular to the longitudinal direction, at the center of the longitudinal direction of the GI zinc-coated steel tube is substantially a V-shape, the V-shape comprising a contacting section in which the inner surfaces of the GI zinc-coated steel tube contact each other. The contacting section is integrated by a Fe-Zn alloy phase. The micro Vickers hardness at a depth of 50 µm from the surface layer of the base metal is 95% or more of the micro Vickers hardness at a depth of 200 µm from the surface layer of the base metal.

The invention discloses a wear-resistant shaft sleeve coating and a preparation method thereof. The wear-resistant shaft sleeve coating comprises the following chemical components in percentage by weight: 0.1-0.5% of C, 10-17% of Ni, 8-12% of Cr, 3-6% of Mo, 0.1-4.5% of TiN and the balance of WC and inevitable impurities. The coating raw materials are proportioned according to the components, then laser cladding is carried out in a reverse synchronous powder feeding mode, a laser cladding layer is formed on the surface of a shaft sleeve, and the wear-resistant shaft sleeve coating is obtained after annealing heat treatment. By designing the comprehensive proportion of the components of the shaft sleeve coating, the laser cladding process and the heat treatment process, the mechanical property of the shaft sleeve coating is comprehensively improved, the service life of the shaft sleeve is effectively prolonged, and the problems that the shaft sleeve coating is prone to stripping, the service life of the shaft sleeve on a machine is short, and the field production efficiency is limited are solved; and a solid foundation is laid for improving the production efficiency and reducing the production cost.

The invention discloses a method for preparing Co-based high-temperature adhesive hard alloy. The method comprises the steps that firstly, CoCl2 6H2O, AlCl3 and deionized water are prepared into a solution, and WO3 powder is added to the solution; a (NH4)2C2O4 solution is added to turbid liquid in volume ratio; the solution is filtered and dried to obtain precursor powder; the dried powder is reduced under the hydrogen atmosphere condition; the reduced powder is subjected to high energy ball milling under argon protection to obtain Co-Al-W prealloy powder; WC and Co-Al-W are subjected to high energy ball milling after being matched, vacuum drying is carried out, and ball milling powder is obtained and placed in a mold for cold pressing forming; and a green ware body obtained after cold pressing forming is sintered, and finally a Co-based high-temperature adhesive hard alloy block is obtained. According to the Co-based high-temperature adhesive hard alloy prepared according to the method, the Vickers hardness is larger than or equal to 1,580 / kg mm<-2>, the bending strength is larger than or equal to 4,958 MPa, and the tensile strength at the temperature of 100 DEG C is larger than or equal to 4,376 MPa.